Fixture for alignment of vacuum nozzles on semiconductor manufacturing equipment

ABSTRACT

An apparatus for measuring and correcting the straightness of a hollow vacuum nozzle for semiconductor assembly equipment comprises a collet which can rotate over 360° and holds the nozzle. An indicator, such as a dial indicator, has a tip which conformally and continuously engages the nozzle so that as the collet and nozzle are rotated the indicator tip rides on the nozzle. Any horizontal movement of a bent nozzle is shown on the indicator. The bend in the nozzle can then be repaired and rechecked while the nozzle is installed in the collet.

This is a continuation of application Ser. No. 08/126,824, filed on Sep.24, 1993, now U.S. Pat. No. 5,433,013.

FIELD OF THE INVENTION

The invention relates to the field of printed circuit assemblymanufacturing, and more specifically to the repair of equipment used toassemble semiconductor devices onto printed circuit boards.

BACKGROUND OF THE INVENTION

To assemble components such as memory devices, logic devices, and otherintegrated circuits onto printed circuit boards, an automated process iscommonly used. One link in the automated assembly process is a pick andplace machine such as the IP-II manufactured by Fuji of Chiryn,Aichiken, Japan. The pick and place machine uses an X-Y positioningsystem and a motorized hollow vacuum nozzle to remove the memorydevice(s) or integrated circuit(s) from a tape and reel feeder, stickfeeder, or waffle tray and place the devices on the printed circuitboard in the correct X, Y, and rotational position. A properlyfunctioning pick and place machine such as the Fuji described above canaccurately place devices to a tolerance of ±0.004 inches.

One problem associated with the vacuum nozzle is that through use thenozzle can become bent which greatly decreases the placement accuracy ofthe machine. To fully calibrate the pick and place machine each nozzlemust be properly aligned. On the Fuji IP-II there are eight nozzles.Bent nozzles are typically returned to the factory for reconditioning orreplacement which requires a number of weeks and a high expense. Thereis a need for an apparatus which allows for a quick and economicalrepair of bent nozzles.

SUMMARY OF THE INVENTION

The apparatus described herein is used for measuring the bend orstraightness of a hollow vacuum nozzle for semiconductor assemblyequipment. The apparatus, in one embodiment, comprises a distanceindicator and an indicator tip movably attached (adjacent) to thedistance indicator. The indicator tip continuously and conformallyengages the hollow vacuum nozzle. The apparatus further comprises acollet capable of rotating 360° for receiving the hollow vacuum nozzle.The apparatus is arranged such that as the collet and the nozzle arerotated the indicator tip rides on the nozzle and the indicatorindicates the position of the indicator tip.

Objects and advantages will become apparent to those skilled in the artfrom the following detailed description read in conjunction with theappended claims and the drawings attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the apparatus; and

FIG. 2 is a side view of a second embodiment of the invention composingan electronic indicator.

It should be emphasized that the drawings herein are not necessarily toscale but are merely schematic representations. Specific structuraldetails can be determined by one of skill in the art by examination ofthe drawing along with the information herein.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a side view of one embodiment of the invention. In thisembodiment, the various elements are positioned on a base 10. A firstelement comprises a bracket 12 mounted to the base 10. The bracket 12receives an interchangeable collet 14, and the collet 14 receives ahollow nozzle 18. In the embodiment shown, the collet 14 is similar tothe collet found on the Fuji IP-II pick and place, although othercollets would function sufficiently due to the ability of the bracket toreceive various collets. The IP-II requires two different types ofnozzles so in this embodiment the apparatus has two interchangeablecollets to receive them. The collet 14 is positioned on a set ofbearings (not shown) and an axle 20 connects the collet 14 to a bottomwheel 22 through the bracket 12. The bottom wheel 22 facilitatesrotation of the collet 14, for example by an equipment technician, andthe collet is such that it can rotate the nozzle 360°. The collet 14receives the hollow nozzle 18.

Also positioned on the base is a magnetic dial indicator stand 24 whichreceives a dial indicator 26 having, for example, a spring loadedindicator tip 28. The indicator tip 28 continuously and conformallyengages the hollow vacuum nozzle 18 such that as the collet 14 and thenozzle 18 are rotated the indicator tip 28 rides on the nozzle 18 andthe indicator 26 indicates the position of the tip 28.

A straight nozzle tested using the apparatus will rotate about itscenter point, and thus the indicator will remain on a single setting. Abent nozzle, however, will rotate about an axis away from its centerpoint and thus the indicator will change with the rotation of thenozzle. In other words, a bent rotating nozzle moves the indicator tiphorizontally and is measured by the indicator, while a straight rotatingtip will have no horizontal movement. If the indicator shows that anozzle is bent, a technician can manually straighten the nozzle, retestit, and provide further adjustment if necessary. A small rod was used toaid in straightening a bent nozzle. It was found that the nozzle wassufficiently straightened by placing a small rod into the end of thehollow vacuum nozzle and using the rod as a lever to straighten thenozzle. The fixture as shown in FIG. 1 provided sufficient support toallow the technician to straighten the nozzle while it was mounted inthe fixture. With the invention as described above, a bend of as littleas 0.001 inches was detected and repaired. As the maximum detectablebend depends on the length of the tip and the resolution of theindicator, the apparatus can be adjusted to allow for the maximumallowable bend.

The indicator used was a dial indicator manufactured by TeclockCorporation of Japan, model number LT-310, although many otherindicators, mechanical 26 (as shown in FIG. 1) or electronical 30 (asshown in FIG. 2) would function sufficiently. The magnetic indicatorstand was a model number 657 manufactured by Starrett of Athol, Mass.The collets for the nozzle were manufactured of steel by an in housemachine shop. The bracket for the collet was manufactured of aluminumand the base was steel, and each was manufactured by an in-house machineshop.

While this invention has been described with reference to illustrativeembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the illustrative embodiments, as well asadditional embodiments of the invention, will be apparent to personsskilled in the art upon reference to this description. For example,various embodiments of the invention can be used to repair otherworkpieces such as other types of nozzles, tubes or pipes. It istherefore contemplated that the appended claims will cover any suchmodifications or embodiments as fall within the true scope of theinvention.

What is claimed is:
 1. A method for straightening a tube, comprising thefollowing steps:a) providing a distance indicator; b) providing acollet; c) placing a tube into said collet; d) providing an indicatortip which indicates a position of said tube; e) rotating said colletthereby rotating said tube, said indicator indicating a position of saidtube; f) straightening said tube with a rod responsive to saidindication, said collet supporting said tube during said straightening.2. The method of claim 1, wherein said step of rotating said collet isrepeated after said step of straightening said tube.
 3. The method ofclaim 1 wherein during said step of rotating said collet, said indicatorindicates horizontal movement of said tube.
 4. The method of claim 1further comprising the step of providing a bracket which positions saidcollet with respect to said indicator tip.
 5. The method of claim 1wherein said tube is a nozzle for semiconductor assembly equipment. 6.The method of claim 1 wherein said tube has a hollow portion therein,and said method further comprises the step of placing said rod into saidhollow portion and straightening said tube responsive to said indicationon said indicator.
 7. A method for bending a workpiece, comprising thefollowing steps:a) providing a distance indicator; b) providing acollet; c) placing a workpiece into said collet; d) moving said colletthereby moving said workpiece, such that said indicator indicates aposition of said workpiece; e) bending said workpiece responsive to saidindication of said workpiece position.
 8. The method of claim 7 whereinsaid collet supports said workpiece during said bending.
 9. The methodof claim 7 wherein during said step of moving said collet, saidindicator indicates horizontal movement of said workpiece.
 10. Themethod of claim 7 further comprising placing a rod into a hollow end ofsaid workpiece during said bending step.
 11. The method of claim 7further comprising the step of straightening said workpiece during saidbending step.
 12. The method of claim 7 wherein said workpiece is anozzle for semiconductor assembly equipment.
 13. The method of claim 7wherein said collet is replaceable.
 14. The method of claim 7, furthercomprising using a rod to aid in bending said workpiece responsive tosaid indication.
 15. The method of claim 7 wherein said workpiece has ahollow portion therein, and said method further comprises the step ofplacing a rod into said hollow portion and straightening said workpieceduring said bending step.
 16. A method for straightening a bend of ahollow vacuum nozzle for semiconductor assembly equipment, comprisingthe following steps:a) providing a distance indicator; b) providing arotatable collet; c) placing a hollow vacuum nozzle into said collet; d)providing an indicator tip movably attached to said distance indicator,said indicator tip engaging said hollow vacuum nozzle; e) rotating saidcollet and said nozzle, said tip riding on said nozzle such that saidindicator tip indicates the position of said nozzle; f) placing a rodinto an exposed end of said hollow vacuum nozzle and bending said hollowvacuum nozzle responsive to said indication on said indicator, saidcollet supporting said nozzle during said bending step.
 17. The methodof claim 16 wherein said collet is rotatable through 360°.
 18. Themethod of claim 16 wherein said step of rotating said collet isrepeated.
 19. The method of claim 16 wherein during said step ofrotating said collet and said nozzle, said collet is rotated whichthereby rotates said nozzle.